1. Field of the Invention
The present invention relates in general to partial combustion processes for forming carbon black, and in particular, to a partial combustion method of forming carbon black from coal in which the ask and char formed in the process are separated from the carbon black.
2. Description of the Prior Art
Methods for producing carbon black from coal are well-known. An example of a fuel-rich or partial combustion carbon black formation process is shown in U.S. Pat. No. 3,773,904. Generally, coal is crushed and introduced with air into a reactor operating at approximately 1200.degree. C. The coal thermally decomposes in the reactor forming flue gases, carbon black, ash and char. The carbon black, ash and char are dry and fine and, therefore, are carried by the rapidly flowing flue gases. This rapidly flowing gas carrying the carbon black, ash and char flows from the reactor to a cyclone for separating the ash and char from the carbon black and flue gas. The flue gases and carbon black are then separated by a water scrubber and electrostatic precipitator. It is also possible to separate the carbon black from the flue gases by means of screens or filters.
A particular problem of the prior art is that char and ash as a produce of carbon black formation is not very useful. Although the char could be used as fuel, it does not have a very high heating value if it contains a significatn amount of ash. Separation of the ash from the char fuel might be accomplished by known separation methods, but such separation methods would be either expensive or inefficient. Accordingly, the char and ash from partial combustion carbon black processes have heretofor not been a particularly desirable product.
It is accordingly an object of the present invention to provide a method of separating char and ash in a partial combustion process of forming carbon black from coal. It is also an object of the present invention to provide such a separation process which is energy efficient and which does not require expensive equipment.